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CAPEC-8: Buffer Overflow in an API Call |
Description This attack targets libraries or shared code modules which are vulnerable to buffer overflow attacks. An adversary who has knowledge of known vulnerable libraries or shared code can easily target software that makes use of these libraries. All clients that make use of the code library thus become vulnerable by association. This has a very broad effect on security across a system, usually affecting more than one software process. Likelihood Of Attack Typical Severity Execution Flow Explore Identify target application: The adversary, with knowledge of vulnerable libraries or shared code modules, identifies a target application or program that makes use of these.
Experiment Find injection vector: The adversary attempts to use the API, and if they can they send a large amount of data to see if the buffer overflow attack really does work. | Techniques |
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| Provide large input to a program or application and observe the behavior. If there is a crash, this means that a buffer overflow attack is possible. |
Craft overflow content: The adversary crafts the content to be injected based on their knowledge of the vulnerability and their desired outcome. If the intent is to simply cause the software to crash, the content need only consist of an excessive quantity of random data. If the intent is to leverage the overflow for execution of arbitrary code, the adversary will craft a set of content that not only overflows the targeted buffer but does so in such a way that the overwritten return address is replaced with one of the adversaries' choosing which points to code injected by the adversary. | Techniques |
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| Create malicious shellcode that will execute when the program execution is returned to it. | | Use a NOP-sled in the overflow content to more easily "slide" into the malicious code. This is done so that the exact return address need not be correct, only in the range of all of the NOPs |
Exploit Overflow the buffer: Using the API as the injection vector, the adversary injects the crafted overflow content into the buffer.
Prerequisites
| The target host exposes an API to the user. |
| One or more API functions exposed by the target host has a buffer overflow vulnerability. |
Skills Required
[Level: Low] An adversary can simply overflow a buffer by inserting a long string into an adversary-modifiable injection vector. The result can be a DoS. |
[Level: High] Exploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level. |
Consequences This table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.| Scope | Impact | Likelihood |
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Availability | Unreliable Execution | | Confidentiality Integrity Availability | Execute Unauthorized Commands | | Confidentiality | Read Data | | Integrity | Modify Data | |
Mitigations
| Use a language or compiler that performs automatic bounds checking. |
| Use secure functions not vulnerable to buffer overflow. |
| If you have to use dangerous functions, make sure that you do boundary checking. |
| Compiler-based canary mechanisms such as StackGuard, ProPolice and the Microsoft Visual Studio /GS flag. Unless this provides automatic bounds checking, it is not a complete solution. |
| Use OS-level preventative functionality. Not a complete solution. |
Example Instances
| Attack Example: Libc in FreeBSD A buffer overflow in the FreeBSD utility setlocale (found in the libc module) puts many programs at risk all at once. |
| Xtlib A buffer overflow in the Xt library of the X windowing system allows local users to execute commands with root privileges. |
References
[REF-1] G. Hoglund and
G. McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. 2004-02.
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Content History | Submissions |
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| Submission Date | Submitter | Organization |
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| 2014-06-23 (Version 2.6) | CAPEC Content Team | The MITRE Corporation | | | Modifications |
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| Modification Date | Modifier | Organization |
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| 2018-07-31 (Version 2.12) | CAPEC Content Team | The MITRE Corporation | | Updated References | | 2021-10-21 (Version 3.6) | CAPEC Content Team | The MITRE Corporation | | Updated Description, Execution_Flow | | 2022-02-22 (Version 3.7) | CAPEC Content Team | The MITRE Corporation | | Updated Skills_Required | | 2022-09-29 (Version 3.8) | CAPEC Content Team | The MITRE Corporation | | Updated Example_Instances |
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